Light-projecting device



9 3 1929iv c. A.B. HALVORSON, JR 1,711,480

LIGHT PROJECTING DEVICE 4 Sheets-Sheet 1 Original Filed March 18, 1925Inventor: I Cromwei Afifialvor fiomdh 9 His Attorney April 3Q 12929 c.A. B. HALVoRsoN. JR

LIGHT PROJEC'TING DEVICE Original Filed March 18, 1925 4 Sheets-SheetF'Lg. 2.

v Inventor". Cromweii Afihalvorsomdr j. A g L 9 n P a m K a m H Uu bApril 36, 1929.

wALvomaoN, JR

LIGHT PROTECTING DEVICE Driginal Filed MarchlB, 1925 4 Sheets-Sheet 3 Aril 30, 1929 C. A. B. HALVORSON, JR LIGHT PROJEG-TING DEVICE OriginalFiled Maf o h- 18, 1925 4 Sheets-Sheet 4 Invento r:

Crornwell Afihalvorsomdr HLS Attomego Patented Apr. 30, 1929.

y UNITED. STATES PATENT OFFICE.

.OROMWELL A. B. HALVORSON, JR., OF LYNN, MASSACHUSETTS, ASSIGNOR TO GEN-ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK,

LIGHT-PROJECTING DEVICE.

Original application filed March 18, 1925, Serial camber 3,1925.

My invention relates to a light projecting device. More in particular,it relates to a device which is especially adapted for use as a traflicsignal.

Among the objects of my invention are to provide an improved projectorin which a hood and a lens are used'and which may be removed as a unit,and to provide-a constructionin which the hood, the lens, the reflectorand the'light source maybe removed as a unit from the projector.

To accomplish the foregoing my invention comprises means hereinaftermore fully set forth and claimed, reference being had to theaccompanyingdrawings in which Fig. 1

shows a pendant type of traffic signal in elevation; Fig. 2 shows asecond form of the traflic signal in perspective with the hood elementremoved; Fig. 3'shows one ofthe hood elements in perspective; Fig. 4shows in perspective one of theprojector elements comprising the hoodelement and the reflector element assembled; Fig. 5 1s a section throughthe projector element of Fig.

4; Fig. 6 shows a'section of the form of housing, a number of which areshownassembled in Fi 1; Fig. 7 shows a standard in section whic isadapted to serve as a support for the form of signal shown in Fig. 1

when it is desired to place the signal upon an upright. Fig. 8 is adrawing on a larger scale than the drawing of Fig. 5 of the reflectorelement of the projector showing the path of the rays. in section andalso shows the focal polnts of the dilferent forms'of surfaces WlllCllgo to make up the reflector.

Referring more in detail to the drawings,

it will be seen that the reflector, Fig. '8, is 40 provided witha rearopening .2 through which a socket for a light bulb may be 111-.- serted.The reflector is also. provided with a front opening 3 through which."the raysthat go to make up the beam from the projectoi' pass-forward.The-rear portion 4 of the reflector immediately around the opening 2 andextending for some distance. there-. from is paraboloidalin form. Beyondthe.

paraboloidal region and "extending as far as the rid 5 the section 6 isspherical. The portion 0 the reflector 7 to the right of the ridge 5 isalso spherical but has a different.

This drawing is shown No. 16,552.. mvi-ded and this application filedDe- 1 Serial 'No. 73,010.

a surface of revolution generated by any one of the conics.

The center of curvature of the spherical region 6 I have indicated atthe point 9. The polnt 10,.on the other hand, is the focal point for theparaboloidal re ions 4 and 8 and the-central point of the sp eric'alregion The reflector, therefore, as shown in. the drawing consists of asurface ofrevolution formed by revolving a curve about the axis.

of the reflector, which axis passes through the focal point 10. Thecurve as shown consists of four conics 4, 6, 7 and 8, three of which,namely, curves 4, 6 and 8, are so positioned with respect to the focalpoint that rays originating in the 'focal point are reflected to. theright of the focal plane, while the fourth curve, namely, curve 7, is sopositioned with respectto the focal point that the rays originating inthe focal point are reflected tf) the left of the focal plane. It willbe seen, therefore, that these conics are all focalizing curves-withtheir concave sides facing toward the focal point, but curves 4, 6 and 8are facing toward the left of the focal plane, while curve 7 is facingtoward the right of the focal plane, The arrows in Fig. 8 indicate howthe rays that go ,to make up a beam from a light source located at thepoint 10 pass out of the reflector. It will be the casing ,is providedwith a flange 11 and with a depression in the form of a forwardlysloping zone 12, (Fig. 5), from the forward end of which zone the collar13 extends. The reflector is mounted with. the outer spherical section?resting against zone 12 of cthe front element. The reflector is clampedin position by means of a number of spring strips 14, the forward endsofwhich are secured to the front plate by means of screws 15. A rearplate 16 serves as a rear support for the reflector and is fastened tothe springs 14: by means of screws 17. This rear support seen that witha reflector of thistype a very is provided with a rearwardly projectingcollar' 18 through which the socket'19 which supports the light sourceprojects. -The center of this light source, it will be understood, isplaced to coincide with the focal point 10, Fig. 8, of the reflector. Itwill be seen that the front plate is provided with a series of screwholes in order that. the projector element may be properly secured tothe casing of the unit, as for example, by means of screws 11, Fig. 2.

The visor 21 otthe projector is made with an annular portion 21 whichserves to hold the lens 22. This lens is locked in position between afelt or rubber cushion on one side and the ring-like spring 23. It willbe seen that to the rear ofthe annular portion 21 there is provided aflange 24 which is split on the underside, Figs. 3 and 5, and by meansof a screw or bolt 25 this flange may be tightly clamped to the collar13 of the front plate.

With this construction if it is desired to remove the electric lamp fromwithin the reflector it is only necessary to loosen the bolt 25 andremove the hood element from the collar 13. The hand may then beinserted through the front opening 3 of the reflector to reach the lamp.In case it is desired to reach-the socket 19 the projector unit may beremoved asa whole by removing the screws 11% It will be understood thatthe cord 26 inside the housing may be made of any suitable length inorder that the projector element may be withdrawn without difiiculty.All of the cables 26 within the unit may be connected to a commonterminal element towhich the.

leads from the source of power fnay be connected. I

The type of easing shown in Fig. 1 is formed of one or more sectionssuch as the section shown in Fig. 6. These sections may be placed one ontop of. another and bolted together each section to the next adjoiningsection for example. For this purpose the lugs 27, Fig. 6, are providedwith suitable holes 28 through which the bolts or screws pass. minalpiece 29 is securedto the lowermost section of the casing.

When the casing is to be mounted on to of a standard such as that shownin Fig. the bottom piece 29 of Fig. -1 is omitted and the casing is seton top, of the upright, Fig. 7, and screwed thereto. For this purposethe lugs 30 with the proper holes for screws or bolts are provided.

The unit in Fig. 1 is provided with a cap piece 31 which is bolted tothe topmost section of the casing in a similar manner. This element 31is provided with an opening on top which is closed by the cap piece 32which latter is suitably'screwed or bolted to the section 31. The crosspiece 33 is in turn secured to the piece 32 and serves as a support forthe wholeunit. Suitable openings are provided through this piece33-through which In a similar manner the bottom ter-' min-ass the cablesor conductors pass into the interior of the un1t, the members 32 and 31bemg,of course, provided with a central opening.

In this trailic signal the visor 21 extends "is to prevent exteriorsources of light, such as the sun or moon or street llghting units,

from striking the lens 22 and making it appear that the signal is inoperation. Heretofore, such exterior sources of light have produced thiseii ect and caused error and confusion in consequence.

While in Fig. 2 the housing has been shown as one continuous sectionthis housing may be constructed with a number of elements, such as shownin Fig. 6, turned at right angles to the position shown in Fig.6. Withsuch an arrangement, however, some of the openings 34 through which theprojector of Fig. 4 is inserted in place may be omitted, for example,the openings which would other- .wise appear on the underside of thecasing in the form of Fig. 2. Although the casing in Fig. 6 is shownwith a straight edge, the construction may be changed to be square toconform with the form indicated in Fig. 2.

It will be understood that whereas I have described my invention inconnection with specific-construction illustrated I do not wish to belimited to such specific construction inasmuch as various modificationsmay be made within the scope of my invention and of the claims hereincontained.

W hat I claim as new and deslre to secure by Letters Patentof the UnitedStates, is

1. In a light projector, a casing, an opening in said casing, saidcasing being provided with a protuberance to one side thereof sur:rounding said opening, a-visor over said opening, means clamping saidvisor to said protuberance, *a lens over the end of said protuberance,means retaining said lens in place, a substantially globular hollowelement in .said casing, means holding said element mounted with itsaxis parallel to the axis of the protuberance and with a portion of onehemisphere of the element seated'in said protuberance, the otherhemisphere of said element being substantially a beam-forming reflector.

2. In a light projector, a casing, an opening in said casing, saidcasing being provided with a protuberance extending to one sidecylindrical portion of said protuberance, of the protuberance and with aportion of the means in said cylindrical band for retaining otherhemisphere thereof-seated in said prosaid lens in place, a hollowglobular member tuberance.

v 10 within saidcasing, one hemisphere thereof In witness whereof, Ihave hereunto set being a beam-forming reflector means holdmy hand vthisfirst dayof December, 1925.

ing said member mounted in said casing with the axis of the memberparallel -to the axis CROMWELL A. B. HALVORSQN, Jr.

